Integrating Anaerobic Digestion Into Our Culture Part 2: Stats, Reality and the Future

North America is at an inflection point in managing organic materials. Just as paper, metal and plastics were the darlings of the recycling industry a couple decades ago, our society is defining a new relationship with organic materials: one that harnesses the full carbon, energy and nutrient potential of organics. In order to help shape that new relationship, industry leaders are cultivating North America's awareness and understanding of anaerobic digestion's features, benefits and potential role in society.

This two-part article explores the ways the waste, energy and agricultural industries are integrating this technology into our culture. In Part One I talked about the people and organizations who are changing the way North Americans think about organics. Here in Part Two, I explore the facts that back up North America's impending adoption of anaerobic digestion, how the transition will happen and what the future might look like.

SUPPORTING ANAEROBIC DIGESTION WITH HARD-HITTING FACTS

Unlike some sexy stories that are filled with hot air, anaerobic digestion — as an efficient technology and tool for economic growth — is backed up by hard-hitting facts. As a technology, anaerobic digestion efficiently unlocks the energies of organics. It is a biological process that happens naturally. We humans have merely figured out ways to make the bacteria extra fat and happy — keep them warm and well fed, floating in a buffered sea of suspended solids — and they will, out of their own volition, reproduce and make biogas. According to a study by Roger Samson and colleagues, the net yield of energy in biogas from corn silage was shown to out-produce ethanol from corn by nearly eight times. Building a digester is like having tenants that, so long as you feed them sugars and starches, pay you back in power and black gold.

The anaerobic digestion industry can also be a tool for jobs, economic development, and security. The Federal Ministry for the Environment has statistics on Renewable Energy Sources that are simply stunning. Germany, which has the largest installed base of solar and the third largest installed base of wind gets more renewable energy from organic materials than wind and solar combined. In addition, the country received an estimated 4.9 billion Euro economic boost from the construction of renewable energy installations in Germany in 2010. Indeed, in 2010 it had approximately 6,000 biogas facilities generating 2,300 MW of electricity, providing power for approximately 4.3 million households (German Biogas Association). In short, Germany serves as a model of a bioenergy economy that produces energy, creates skilled jobs, improves energy independence and stimulates economic growth (BMU).

North America, while a couple decades behind on this path, could see a similar renaissance in its renewable energy cards with its larger sources of food waste, more cows, more land and more population. The U.S. has already projected the potential of biogas with its Billion Ton Biomass study, which as summarized by Jim Lane of Biofuels Digest, “projected that the U.S. would have between 1.1 and 1.6 billion tons of available, sustainable biomass for industrial bioprocessing by 2030.” This industry is poised to grow and power us forward into a new bioenergy economy.

BUILDING THE BRIDGE BETWEEN CONCEPT AND REALITY

Marketing aside, building digestion projects comes with a unique set of challenges. Harvest and its development of digesters, or rather its Energy Gardens, in Richmond, BC and London, ON serves as a window into creating successful projects. This section looks at a few factors — site control, permitting, financing, public policy, construction details, feedstock supply, and power off-take agreements — that must align to build projects that work.

The Energy Garden in Richmond BC, a high solids anaerobic digester, will process approximately 30,000 tons of organic materials per year producing 2 MW of combined heat and power. The Energy Garden in London ON, a continuously stirred tank reactor anaerobic digester, will have the capacity to process 70,000 short tons per year producing 5.7 MW of heat and electricity. For site control, the Richmond digester is located on the footprint of a pre-existing composting operation, adding a symbiotic relationship to the site by harnessing the energy from the food wastes with higher caloric value. London was a blank slate built from the ground up. For permitting, the biggest barrier in general is that the biogas industry is rather new, so we have to explain the technology and features. For financing, there were benefits from incentives such as a $4 million grant from Natural Resources Canada and a $1.5 million loan and grant from BC Bioenergy Network.

Perhaps the biggest hurdle in developing projects is North America’s renewable energy policy. Public policy does not support the science. Biogas is the most efficient conversion of biomass into energy, yet drop in biofuels industries like ethanol and algae biodiesel reign supreme. Ontario is an outlier: under its Green Energy Act, the Ministry of Energy has facilitated a streamlined process that guarantees specific rates, also known as a feed-in tariff, for energy generated from renewable sources. British Columbia has also aligned programs and policies to stimulate bioenergy projects. U.S. policy remains confused but is slowly changing.

Unlike construction in Europe, anaerobic digestion construction is still a nascent market. Thus the supply chain and body of constructors is limited, making it is difficult to source competitive construction pricing. For feedstock supplies, grassroots support is vital. Just as other renewables are situational — solar power needs sun, wind power needs wind, tidal needs flowing water — anaerobic digestion requires community participation to separate organic wastes out of the traditional disposal option. Collecting your power feedstock from the public comes with its own measure of opportunities and challenges, which are perhaps fodder for another article.

Finally, for power off-take agreements, the Richmond project will produce energy under BC Hydro’s Community Based Biomass Power Call. In London an agreement was reached with the Ontario Power Authority under the Renewable Energy Standard Offer Program.

AN ORGANICS OPERATING SYSTEM FOR THE FUTURE

Anaerobic digestion is telling a good story, but we as a whole still have room to grow. We will continue to tell the story of a new path for organics through provocative visitors’ centers at its Energy Gardens, open houses, conversations with thought leaders across the sectors, and stimulation of the senses in its sales and marketing. Community support is a part of our measurement of success.

It’s about people, and people caring about our natural resources. It’s about materials, and putting them to their highest and best use. It’s about energy, and how we create it, reduce our consumption, and increase our independence. It’s about nutrients, and building soil health that directly translates to community health. It’s about interlocking connections, and the infinite synergies between waste, energy and agriculture. Food security. Clean rivers. Fresh air. Reduced greenhouse gas emissions. Reduced chemical fertilizer use. Increased recycling. Soil fertility. Reduced erosion. Local, firm, renewable, clean energy. The overlaps and interlocking solutions are fascinating, and we’ve only just begun.

This new approach, an “Organics Operating System,” allows us to unlock the powerful potential in our hands and at our feet. It’s a new relationship with organic materials as anaerobic digestion gets woven into our culture.

The city of Portland OR has been using methane in fuel cells to use methane captured from sewage treatment at the Columbia Treatment Facility for the last 13 years. They generate 200Kw that is sufficient to run the plant. The cost of fuel cells has gone down considerable since the system was first installed.

Bob----Caterpillar has made several models of diesel generators for almost 60 years,(8 I think)---ranging in size from 45 hp(about 30 Kw) to something like 4500 hp(about 3Mw---diesel locomotive size). They can be ordered to run on field or biogas(field gas is natural gas straight from the well head, unscrubbed, biogas is essentially the same thing) or utility grade methane(scrubbed, 99+% CH4---what you get from the utility in your home). Using CHP(combined heat & power), it is possible to get around 80-90% thermal efficiency.

Fuel cells are another option. There are several different types available---and they can be tailored to meet the operator needs.

Interesting links fred. The digestor at the WW plant seems to function in much the same way. Perhaps the existing digestor can be adapted to take waste from the farms in town in order to produce more methane. Then perhaps instead of burning the methane it can be used to power a generator to produce electricity.

Many waste water treatment plants have anaerobic digestors. The biological process is used to break down incoming waste and a main output of the project is methane which is used to heat the plant and reduce energy costs. Unfortunately, some plants like the one I interned at just burn off the excess methane when the plant does not need any heat. This is such a waste. Are there any proven processes out there to capture excess so that it can possibly be sold off?

Since the companies that own the natural gas pipelines own or partner with the companies that own the gas wells, I doubt that they will offer you competitive prices on your biogas. What is needed is a cooperative of biogas producers to band together to market their gas locally or regionally as a liquid fuel. Natural gas is unregulated, and because of the new supplies through fracking, there is a glut of supply. One gas company just shut production at 25% of its wells which led to an immediate rise of 8% on the gas market.
I would like to see this technology applied in such a way that small farms could afford to use the technology, but from what I understand, a digester for 250 dairy cows costs about a million US dollars, and that is about the smallest size available.

Add another synergy with thermal conversion systems for biochar production, compost with the char to retain a majority of normally volatilized NH3.
Recent work by C. Steiner, at U of GA, showing a 52% reduction of NH3 loss when char is used as a composting accelerator. This will have profound value added consequences for the commercial composting industry by reduction of their GHG emissions and the sale of compost as an organic nitrogen fertilizer. http://www.ibi2010.org/wp-content/uploads/BiocharPoultrySteiner.pdf

How about using the same technology to reduce the amount of conventional power usage in the distillation process for ethanol producers? This would greatly increase their advantage in a carbon based tax or exchange system.

The utility of such systems was made clear to me in Hawaii serveral years ago. There the Sand Island Sewage plant flared off the only hydrocarbons generated with the islands.

For our part, Futura Solar has several times proposed our Sawtooth Solar Daylighter as part of such processing facilities. This system daylights, and gathers solar thermal (air & water) to facilitate that digestion, while reducing the power required to operate the facility. We still look forward to marrying the two ideas to the benefit of all.

Looking at the economics, the Richmond, BC plant producing 2MW would generate $876,000 of revenue per year at $0.05 per KWH. I can generate $3,000,000 of revenue per year of livestock feed and compost using Black Soldier Fly Larvae to recycle the same amount of waste. Anyone interested in doing a project, leave a post.

The obstacles are no longer mixing different organic feedstock; but governmental. The U.S. is not Europe or Canada with almost seemless socialized service delivery and cooperation, so someone has to broker deals with public works depts, private haulers, septage companies and regional sewerage treatment agencies....and run the whole thing through a gauntlet of permitting and public comment.

In Maine we are witnessing a major expansion of natural gas pipelines, making selling bio-gas to them a possibility. Compressing the gas opens doors to converting and fueling public fleets and buildings.

I am quite happy to have a growing vendor community who will even turn key A.D.'s....so that if a suitable coalition of public agencies can be organized, the next step is issuing an RFP to these vendors.

ONTARIO def. pulled all the right elements together in one coherent implementation package...from financial incentives to on site evaluations and even imported operator training...the result of over 30 AD's in one year is a stunning success! Apparently TORONTO even converted a composting operation over to anaerobic digestion!

How about heat for the homeless in urban environments by composting organic waste? I imagine some type of cylindrical aerobic/anaerobic combi-system where the community could donate their organic waste for a helpful cause.